Recently, stem cells of organisms (tissues) specific to a variety of organs or tissues have been found to play significant roles in maintenance and regeneration of the relevant organs or tissues. Up to the present, stem cells derived from a variety of tissues have been reported and isolated.
Examples of stem cells isolated to date include skeletal muscle stem cells, cardiac muscle stem cells, liver stem cells, neural stem cells, pancreatic stem cells, epidermal stem cells, and adipose tissue stem cells. Stem cells are often isolated by the side population (SP) method, and the present inventors previously isolated the smooth muscle stem cells from the human uterus by the SP method (see JP Patent Publication (kokai) No. 2007-202435 A).
At present, regenerative medicine has drawn a great deal of attention as a form of medical treatment for restoring cells or tissues of human bodies that have been damaged or lost due to diseases or injuries and recovering the functions thereof. If the above tissue stem cells could be isolated, identified, replicated and multiplied, it would be possible to achieve regenerative medical treatments.